Gymnastic machine

ABSTRACT

Gymnastic machine ( 1 ) for performing walking or running exercises along a given direction (D) includes a frame ( 10 ) and an endless belt ( 20 ) wound in a loop on a pair of rollers ( 30 ) carried by the frame ( 10 ) transversely to the given direction (D), with a tensioning device ( 40 ) provided in association with at least a first of the rollers ( 30 ) to maintain the belt ( 20 ) longitudinally tensioned in a uniform manner and with a centering device ( 60 ) provided to maintain the belt ( 20 ) disposed substantially equidistant from first lateral end portions ( 32 ) of each roller ( 30 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a gymnastic machine for performing fast walking and/or running exercises. In particular, the present invention relates to a gymnastic machine for performing fast walking and/or running exercises provided with a belt. In more detail, the present invention relates to a gymnastic machine for performing fast walking and/or running exercises provided with an endless belt wound in a loop on a pair of rollers and comprising a device for adjusting the position of the belt on said rollers.

2. Description of the Prior Art

There are well-known machines for performing fast walking and/or running exercises, which are provided with an endless belt wound in a loop on two rollers carried by a frame and which can be actuated by an electric motor interacting with one of the two rollers, or be carried idle and actuated through the friction produced between the internal surface of the belt and the surface of the rollers due to the traction exerted by the belt on said rollers, which maintains the belt sufficiently tensioned over a table disposed between the rollers and suitable to support a user exercising.

Incidentally, it must be noted that the gymnastic machines described above are commonly called treadmills. Therefore, here and hereunder this term is used to indicate these types of machines.

In view of the above description, the user runs on the endless belt and receives therefrom a thrust with each step. Therefore, the possibility of maintaining his/her balance depends on the action reciprocated by the belt when his/her foot strikes the belt, causing it to flex. It is clear that the optimal situation is attained when the belt remains centred on the rollers during travel, given that in this way the thrust that the user exercising receives from the belt turning on the rollers is longitudinal, and consequently directed according to the direction of feed of the belt. In this case, as the lateral deviatoric component exerted by the belt on the feet of the user exercising is null, it is consequently easier to maintain balance during fast running, given that in this case the power transmitted from the rollers to the belt, and consequently to the feet of the user, is maximum. Conversely, again during fast running, the presence of deviatoric components that are not null and/or variable in terms of direction can considerably disturb movement of a user on the belt, and compromise balance by transmitting stresses of different degrees and levels to the foot.

Moreover, the optimal situation described above is not found frequently, and it is normal for endless belts to have ends which are maintained in position through lateral sections of increased dimension acting as stops for the edges of the belt. It must be noted that this solution of the technical problem proposed above has some drawbacks, such as rapid wear due to the belt rubbing on the rollers or at the lateral sections of increased dimension, which causes premature wear on the edges of the endless belt, given that it is shaped to withstand frictional stresses acting on the inner face due to rolling contact with the rollers and due to contact with a deck below a feed branch of the endless belt produced by periodic beating of the foot that travels and pushes on the belt while the latter is moved backward.

The solution has been borrowed from the conveyor belt sector of tapering the idle rollers, producing each of the lateral end portions of the rollers in the shape of a truncated cone of a length that is slightly less than a third of the total extension of said roller. Nonetheless, the implementation of this solution is difficult in the sector of endless belts for gymnastic machines, given that the upper surface of the endless belt can be globally perceived as being substantially hump-backed, and can therefore cause disorders affecting the articulations of the lower limbs of users. Furthermore, it has been noted that this structure of the rollers causes the endless belt to curl at respective lateral end portions. This curling is a consequence caused by the fact that the belt is not rigid and that, due to conicity, lateral thrusts act constantly on the lateral edges thereof, tending to conduct the edges of the endless belt towards the centre. This situation is encountered indefinitely during operation, irrespective of the position, centred or not, taken by the endless belt on the rollers and, due to this curling, the endless belt has undulations that also spread to the central portion thereof. Therefore, the surface on which users run is no longer flat and consequently becomes potentially dangerous. Moreover, besides lowering the level of safety of the gymnastic machine in its entirety, the presence of these undulations also causes premature wear of the endless belt.

With regard to the description above, which mirrors the current situation, the problem of maintaining the endless belt centred on the rollers is currently unsolved, and represents an interesting challenge for the applicant for the purpose of improving operation of treadmills and comfort of the users who use them, but also of minimising maintenance operations on these types of gymnastic machines and of increasing distribution and economic yield of the respective production chain.

In view of the situation described above, it would be desirable to obtain a gymnastic machine provided with an endless belt which, besides making it possible to limit and possibly overcome the typical drawbacks of the known prior art illustrated above, could also define a new standard in the treadmill sector.

An object of the present invention is to construct a gymnastic machine for performing fast walking and/or running exercises that allows the disadvantages described above to be solved, and which is suitable to satisfy a plurality of requirements that to date have still not been addressed, and therefore, suitable to represent a new and original source of economic interest, capable of modifying the current market of treadmills.

A further object of the present invention is to construct an endless belt for a gymnastic machine for performing fast walking and/or running exercises able to minimise maintenance on said gymnastic machine and to increase distribution thereof and the economic yield of the respective production chain.

A still further object of the present invention is to provide a method for constructing an endless belt for a gymnastic machine for performing fast walking and/or running exercises.

These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a gymnastic machine for performing walking or running exercises along a direction of feed and including a frame and an endless belt wound in a loop on a pair of rollers carried by said frame transversely to the direction of feed, centering means of geometrical type suitable to maintain the belt disposed substantially equidistant from first lateral end portions of each roller, by providing an annular endless belt for the gymnastic machine and having a cross section with a rectilinear central portion delimited by the second lateral portions shaped for shape coupling with the lateral end portions of at least one roller; and by providing a method for producing an annular endless belt for the gymnastic machine and including cutting a plurality of panels substantially rectangular in shape and substantially identical to one another and delimited by a pair of the lateral sides substantially parallel to each other and by a first side and a second side transverse to the direction of feed, and stitching the panels to one another to couple one first side and one second side so as to determine a curvature of the lateral edge of the belt which corresponds to a shape coupling of the second lateral portions of the belt with the arched first lateral end portions of the rollers.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the machine according to the present invention will be more apparent from the description below, set forth with reference to the accompanying drawings, which illustrate some non-limiting examples of embodiment, in which identical or corresponding parts of the device are identified by the same reference numbers.

In the drawings:

FIG. 1 is a perspective schematic view of a preferred embodiment of a gymnastic machine according to the present invention;

FIG. 2 is a schematic side elevation view of FIG. 1;

FIG. 3 is a side elevation view in enlarged scale of a detail extracted from FIG. 2;

FIG. 4 is a perspective view of a variant of a second detail extracted from FIG. 2; and

FIG. 5 is a plan view in enlarged scale of a third detail extracted from FIG. 4;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, no. 1 indicates, in its entirety, a gymnastic machine for performing walking, fast walking and/or running exercises along a given direction D of feed and comprising a frame 10, an endless belt 20 wound in a loop on a pair of rollers 30 carried by the frame 10 transversely to the direction D of feed to distinguish an upper conveying branch 22 from a lower free branch 24. The machine 1 further comprises a tensioning device 40 carried by the frame 10 in association with at least a first roller 30 to maintain the belt 20 longitudinally tensioned in a uniform manner along the width thereof. The machine 1 presents, between the rollers 30, a deck 50 carried by the frame 10 to support a user exercising on the belt 20. The machine 1 further comprises a centering device 60 suitable to maintain the belt 20 disposed substantially equidistant from lateral end portions 32 of each roller 30.

The centering device 60 is designed so as to cooperate with the tensioning device 40 in order to determine variations of the distribution of the tension of the endless belt 20 so as to condition transverse positioning thereof on the rollers 30. In particular, with specific reference to FIG. 3, the centering device 60 comprises the lateral end portions 32 of at least one roller 30, due to the fact that such lateral end portions 32 present a substantially arched longitudinal section whose radius R of curvature is between 0.7 and 0.9 times a width H of the endless belt 20 (FIG. 1), in relation to the elastic characteristic of the material with which the belt 20 is constructed. It should be noted that the repositioning/realignment speed of the belt 20 will also be influenced by the transverse elasticity/rigidity thereof. In particular, with the same elasticity of the belt 20, the lower the radius of curvature of lateral end portions 32 of each roller 30 is, the greater the centering effect occurring on the belt 20 will be.

In view of the above description, it is understood that the lateral end portions 32 of at least one roller 30 have an arched section for shape interaction with lateral portions 26 of the endless belt 20, so as to determine, in use, localised variation of the direction of the resultant of the tension applied laterally to the belt 20, and therefore at such lateral portions. This allows production of a transverse thrust of a level proportional to the overlapping/degree of overlapping of the lateral end portions 32 of each roller 30 by the lateral portions 26 of the belt 20, which is accompanied by a realignment speed of the belt 20 directly proportional to the overlapping/degree of overlapping.

In view of the above description, the centering device 60 is a device whose operation is based on a principle of an essentially geometrical nature.

It must be noted that both FIG. 1 and FIG. 2 have been drawn purposely limiting the structural contents of the machine 1 to the essential to make it evident that the description above, and below, has general validity as it refers to structural elements common to all treadmills. For the same reason, the device 40 has been schematically illustrated in FIGS. 1 and 2 through a carriage support 42 carried movable exclusively along the direction D of feed through a tie rod 44 operatable through an operating nut 46.

In addition, purely for the purpose of providing some constructional specifications that make the machine 1 particularly well proportioned and without limiting the scope of the present invention, it may be advisable to specify that to dimension the machine 1 with proportions that make it perfectly suitable for use by users both small and large in size, both for performing slow or fast walking exercises and for performing fast running exercises, i.e. around 25 km/h, it is practical for the lateral end portions 32 to be dimensioned so that they extend transversely for a length between 0.06 and 0.1 times the width H of the endless belt 20 (FIG. 3).

Naturally, the above description can be validly applied both to treadmills provided with their own feed unit of the endless belt 20, typically a rotary electric motor which is connected mechanically to one of the rollers 30 to enable it to exert a pulling action on the belt 20 and on the other roller 30, to condition a step frequency of the user, and consequently also encourage him/her to follow a specific training programme. In any case, it should be specified that shaped rollers 30 as described above can also be validly applied to gymnastic machines in which feed of the belt 20 is determined by dragging of the belt produced by friction between the feet of a user and the belt 20 on the upper branch 22 thereof.

Use of the machine 1 is easily understood from the above description and requires no further explanation. Furthermore, it may be worthwhile to observe that the endless belt 20 must present, in the loadless condition, a substantially flat shape, so that it is smooth once it has been positioned equidistant from the lateral end portions 32 of the rollers 30, and consequently coupled exclusively with a central portion 34 of the roller 30. In addition, the material with which the belt 20 is constructed must be such as to combine durability, resistance to friction with the rollers and with the deck, but also sufficient elasticity to allow the belt to couple with the lateral end portions 32 of the rollers 30, and therefore to copy their shape also when the belt 20 is moved laterally from the position centred on said rollers 30. Naturally, to obtain this result, action must be taken on the tensioning device 40, in order to suitably adjust the longitudinal tension on the belt 20.

As will have been noted, it has been considered superfluous to specify whether the machine 1 is provided with a device to drive the belt 20, given that this specification lies outside the object of the present invention, which can also be validly applied to gymnastic machines provided with or without a device of this type.

Finally, it is clear that modifications and variants can be made to the gymnastic machine 1 described and illustrated herein without however departing from the protective scope of the present invention.

Furthermore, to complete the above description, it is deemed appropriate to specify that the result described above can also be achieved with suitably shaped belts 20. For example, with reference to FIG. 4, it could be advantageous to construct the belt 20 so that the respective cross section presents a rectilinear central portion 28 delimited by the lateral portions 26 shaped for shape coupling with the lateral end portions 32 of the rollers 30 when the belt 20 is positioned equidistant from such lateral portions 32. Naturally, this choice could influence the choice of material of the belt which, to prevent dangerous bulging during the steps of shifting from the position centred on the rollers 30, would have to be particularly elastic for copying of the shape of the lateral end portions 32 of the rollers 30 to be maintained constant.

In this regard, it could be worthwhile to use a production method of the belt 20 of FIG. 4 borrowed from the methodology to produce sails which, as is known, are produced by assembling panels, or sail panels, along respective sides which, in use, will be substantially parallel to the direction of membranal stress to which they will be subjected. In fact, it is known that to obtain a desired distribution of the deflection under load, each sail panel is cut with the coupling sides profiled in a different way and, in particular, a first side is cut in an arch and the other is cut rectilinear although both present the same linear extension as the side with which they are to be connected by stitching or bonding, so as to maintain each side of the sail globally smooth. The shape of the profile of the arched side will determine the shape of the profile of the sail, and consequently distribution of the deflection under load. Returning to the belt 20, in view of the above description, it could be advisable to produce said belt 20 by assembling panels 29 substantially identical to one another, each of which is reproduced in FIG. 5. Each panel 29 is delimited by a first side A transverse to the direction D and Arched in a convex fashion, and by a second side B, opposite the side A and substantially rectilinear. Naturally, the sides A and B are connected to each other by lateral sides L which, in use, are oriented substantially in the direction D of feed. For this reason, they must be substantially parallel with each other, but must be shaped so that assembly of each side A with each side B produces a profile that faithfully follows the shape of the roller 30 but is smooth once the device 40 has be adjusted to subject the belt 20 to the longitudinal operating tension. Therefore, each transverse side A presenting a substantially rectilinear central portion C delimited by two arched edges E symmetrical with each other so as to create the desired lateral bulge. Moreover, the sides L can be inclined with respect to each other like the sides of an isosceles trapezoid. Naturally, in FIG. 5 the panel 29 is illustrated so as to overemphasise the geometrical characteristics of the sides that delimit said panel, so as to make them more evident, although this makes the panel 29 of FIG. 5 differ from the real one.

Therefore, the production method must include a step of cutting a plurality of panels 29 in the shape of isosceles trapezium presenting two non-parallel sides inclined at a minimum angle so as to substantially approximate a rectangular shape. Therefore, each panel 29 will be delimited by a pair of lateral sides L inclined but substantially parallel to each other and in any case reciprocally inclined in relation to the ratio between the length of the respective sides A and B. It is clear that each panel must be cut in such a way that the linear extension of the arched first side A approximates, but is slightly less than, the linear extension of the second side B to which it is connected.

In the case of wishing to transform a treadmill already available so that the position of the respective endless belt is maintained centred as described above with reference to the machine 1, it could be advisable to replace the rollers with rollers 30 of a length and diameter suitable for the model of treadmill, or to modify the respective rollers in the respective end portions so as to allow coupling with lateral portions 26 which should be shaped to couple seamlessly with the central portion 34 of the roller, and therefore so as to reproduce, in a suitable scale, the profile of the rollers 30 described above with reference to the machine 1.

From the description above, it is apparent that each roller of a treadmill, differing from the machine 1 described above and produced directly or assembled so as to reproduce the shape of each roller 30 and consequently determine in use the occurrence of membranal stresses in the corresponding endless belt similar to those that the roller 30 determines in use in the belt 20, will fall within the scope of protection of the present invention.

Finally, the teachings provided above allow the construction of a gymnastic machine provided with an endless belt that overcomes the typical drawbacks of prior art and is consequently a candidate for defining a new standard in the sector of treadmills. It must be noted that the higher the elasticity of the belt 20 is, the more it is possible to concentrate reduction of the diameter in the lateral end portions 32 in a reduced length and maintain an efficient centering effect on the belt 20, which will tend to be repositioned more rapidly in the centred position thereof due to its capacity to follow the variations of the shape of the roller 30 at the respective lateral end portions 32, naturally, in use, when misalignment occurs.

Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims. 

1. A gymnastic machine (1) for performing walking or running exercises along a direction (D) of feed and comprising a frame (10) and an endless belt (20) wound in a loop on a pair of rollers (30) carried by said frame (10) transversely to said direction (D) of feed, characterized by comprising centering means (60) of geometrical type, suitable to maintain said belt (20) disposed substantially equidistant from first lateral end portions (32) of each said roller (30).
 2. A machine according to claim 1, characterized by comprising tensioning means (40) carried by said frame (10) in association with at least a first of said rollers (30) to maintain said belt (20) longitudinally tensioned in a uniform manner; said centering means (60) being designed to cooperate with said tensioning means (40) in order to determine localised variations of the distribution of the tension of said endless belt (20) to condition transverse positioning thereof.
 3. A machine according to claim 2, characterized in that said centering means (60) are shape centering means.
 4. A machine according to claim 3, characterized in that said centering means comprise said first lateral end portions (32) of at least one said roller (30).
 5. A machine according to claim 4, characterized in that each said first lateral end portion (32) is shaped for shape interaction with said endless belt (20) at respective second lateral portions (26).
 6. A machine according to claim 5, characterized in that each said first lateral end portion (32) presents a longitudinal section shaped so as to determine, in use, a variation of the direction of the resultant of the tension applied laterally to said belt (20) at the relative said second lateral portion (26), in order to produce a transverse thrust on said belt (20) of a level proportional to a degree of overlapping of said first lateral end portion (32) by said second lateral portion (26) of said belt (20).
 7. A machine according to claim 1, characterized in that each said first lateral end portion (32) is delimited by a substantially arched longitudinal section.
 8. A machine according to claim 7, characterized in that each said first lateral end portion (32) presents a radius (R) of curvature between 0.7 and 0.9 times a width of said endless belt (20).
 9. A machine according to claim 7, characterized in that each said first lateral end portion (32) extends transversely for a length between 0.06 and 0.1 times the width of said endless belt (20).
 10. A roller (30) for a gymnastic machine (1) for performing walking or running exercises along a direction (D) of feed and described with reference to at least one of the preceding claims, characterized by comprising respective said first lateral end portions (32) presenting a longitudinal section shaped so as to determine, in use, a variation of the direction of the resultant of the tension applied laterally to said endless belt (20) at respective said second lateral portions (26), in order to produce a transverse thrust of a level proportional to a degree of overlapping of said first lateral end portions (32) by said second lateral portions (26) of said belt (20)
 11. A roller according to claim 10, characterized in that the first lateral end portions (32) are delimited by a substantially arched longitudinal section.
 12. A roller according to claim 11, characterized in that each said first lateral end portion (32) presents a radius of curvature between 0.7 and 0.9 times a width of said endless belt (20).
 13. A roller according to claim 11, characterized in that each said first lateral end portion (32) extends transversely for a length between 0.0 and 0.1 times the width of said endless belt (20).
 14. An annular endless belt for a gymnastic machine for performing walking or running exercises along a direction (D) of feed and described with reference to claim 1, characterized by presenting a cross section comprising a rectilinear central portion (28) delimited by said second lateral portions (26) shaped for shape coupling with said first lateral end portions (32) of at least one said roller (30).
 15. A belt according to claim 14, characterized in that said second lateral portions (26) have an arched cross section for shape coupling with said first lateral end portions (32) of at least one said roller (30) when, in use, said belt (20) is positioned equidistant from said first lateral end portions (32) of at least one said roller (30).
 16. A belt according to claim 15, characterized in that at least said second lateral portions (26) are produced with elastic material for shape coupling with said first lateral end portions (32) of at least one said roller (30)
 17. A belt according to claim 14, characterized by comprising a plurality of panels (29) substantially identical to one another, each of which is delimited by a first side (A) and by a second side (B) transverse to said direction (D) of feed and by two lateral sides (L).
 18. A method for producing an annular endless belt for a gymnastic machine for performing walking or running exercises along a given direction and described with reference to claim 14, characterized by comprising a step of cutting a plurality of panels (29) substantially rectangular in shape and substantially identical to one another and delimited by a pair of said lateral sides (L) substantially parallel to each other and by a said first side (A) and a said second side (B) transverse to said direction (D) of feed; a step of stitching said panels (20) to one another to couple one said first side (A) and one said second side (B) so as to determine a curvature of the lateral edge of said belt (20) which corresponds to a shape coupling of said second lateral portions (26) of said belt with arched said first lateral end portions (32) of said rollers (30).
 19. A method according to claim 18, characterized in that said first side (A) is substantially rectilinear; said second side (B) presenting a substantially rectilinear second central portion (C) delimited by two arched edges (E) symmetrical with each other, so as to create a curvature of the lateral edge of said belt (20).
 20. A method according to claim 19, characterized by comprising the step of cutting each said panel (29) with the respective said third lateral sides (L) inclined with respect to each other so that the linear extension of each said first side (A) approximates, but is slightly less than, the linear extension of the respective second side (B) to which it is coupled. 